Extrinsic 18337-1

{
  "heartbeat": {
    "blockNumber": 18335,
    "sessionIndex": 305,
    "validatorsLen": 4,
    "authorityIndex": 2
  },
  "signature": "0xeeccf9c2bdca992ce653896ae4afaf149ecb9f198cf4e8808497ff4b38caad4b18e2a4f5d6ee72316ed26934998280dfee62d31e05f687d86af4cbc63ce24986"
}